arm64: move the (z)install rules to arch/arm64/Makefile

Currently, the (z)install targets in arch/arm64/Makefile descend into
arch/arm64/boot/Makefile to invoke the shell script, but there is no
good reason to do so.

arch/arm64/Makefile can run the shell script directly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210729140527.443116-1-masahiroy@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 7bc37d0..ded1323 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -165,8 +165,11 @@
 Image.%: Image
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
-zinstall install:
-	$(Q)$(MAKE) $(build)=$(boot) $@
+install: install-image := Image
+zinstall: install-image := Image.gz
+install zinstall:
+	$(CONFIG_SHELL) $(srctree)/$(boot)/install.sh $(KERNELRELEASE) \
+	$(boot)/$(install-image) System.map "$(INSTALL_PATH)"
 
 PHONY += vdso_install
 vdso_install: